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Monday, August 27, 2007

Herbal medicine, also called botanical medicine or phytomedicine, refers to the use of any plant's seeds, berries, roots, leaves, bark, or flowers for medicinal purposes. Long practiced outside of conventional medicine, herbalism is becoming more mainstream as up-to-date analysis and research show their value in the treatment and prevention of disease.

How do herbs work?

For most herbs, the specific ingredient that causes a therapeutic effect is not known. Whole herbs contain many ingredients, and it is likely that they work together to produce the desired medicinal effect. Many factors affect how effective an herb will be. For example, the type of environment (climate, bugs, soil quality) in which a plant grew will affect its components, as will how and when it was harvested and processed.

How are herbs used?

For the reasons described in the previous section, herbalists prefer using whole plants rather than extracting single components from them. Whole plant extracts have many components. These components work together to produce therapeutic effects and also to lessen the chances of side effects from any one component. Several herbs are often used together to enhance effectiveness and synergistic actions and to reduce toxicity. Herbalists must take many things into account when prescribing herbs. For example, the species and variety of the plant, the plant's habitat, how it was stored and processed, and whether or not there are contaminants.

What is herbal medicine good for?

Herbalists treat many conditions such as asthma, eczema, premenstrual syndrome, rheumatoid arthritis, migraine, menopausal symptoms, chronic fatigue, and irritable bowel syndrome, among others. Herbal preparations are best taken under the guidance of a trained professional. Be sure to consult with your doctor or an herbalist before self-treating. Some common herbs and their uses are discussed below.

Ginkgo ( Ginkgo biloba ), particularly a standardized extract known as EGb 761, appears to produce improvements in awareness, judgment, and social function in people with Alzheimer's disease and dementia. In a year-long study of 309 people with Alzheimer's disease, those taking EGb 761 consistently improved while those on placebo worsened.

Kava kava ( Piper methysticum ) has become popular as a treatment for anxiety, but recent reports have traced liver damage to enough people who have used kava that the U.S. FDA has issued a warning regarding its use and other countries, such as Germany and Canada, have taken kava off of the market.

St. John's wort ( Hypericum perforatum ) is well known for its antidepressant effects, and an analysis of 27 studies involving more than 2,000 people confirmed that the herb is an effective treatment for mild to moderate depression.

Valerian ( Valeriana officinalis ) has had a long tradition as a sleep-inducing agent, with the added benefit of producing no hangover feeling the next day.

Echinacea preparations (from Echinacea purpurea and other Echinacea species) may bolster immunity. In a study of 160 volunteers with flu-like symptoms, echinacea extract reduced both the frequency and severity of cold symptoms.

Is there anything I should watch out for?

Used correctly, many herbs are considered safer than conventional medications, but because they are unregulated, herbal products are often mislabeled and may contain undeclared additives and adulterants. Some herbs are associated with allergic reactions or interact with conventional drugs. Self-prescribing herbal products will increase your risk, so it is important to consult your doctor and an herbalist before taking herbal medicines. Some examples of adverse reactions from certain popular herbs are described below.

St. John's wort causes sensitivity to the sun's ultraviolet rays, and may cause an allergic reaction, stomach upset, fatigue, and restlessness. Studies show that St. John's wort also interferes with the effectiveness of many drugs, including warfarin (a blood thinner), protease inhibitors for HIV, possibly birth control pills, and many other medications. In addition, St. John's wort must not be taken with anti-depressant medication. The Food and Drug Administration (FDA) has issued a public health advisory concerning many of these interactions.

Kava kava and echinacea have both been linked to liver toxicity. Again, kava has been taken off the market in several countries because of the liver toxicity.

Valerian may cause oversedation, and in some people it may even have the unexpected effect of overstimulating instead of sedating.

Feverfew ( Tanacetum parthenium ) may cause agitation.

Bleeding time may be altered with the use of garlic, ginkgo, feverfew, ginger ( Zingiber officinale ) and ginseng.

How is herbal medicine sold in stores?

The herbs available in most stores come in several different forms: teas, syrups, oils, liquid extracts, tinctures, and dry extracts (pills or capsules). Teas are simply dried herbs left to soak for a few minutes in boiling water. Syrups, made from concentrated extracts and added to sweet-tasting preparations, are frequently used for sore throats and coughs. Oils are extracted from plants and often used as rubs for massage, either alone or as part of an ointment or cream. Tinctures and liquid extracts are solvents (usually water, alcohol, or glycerol) that contain the active ingredients of the herbs. Tinctures are typically a 1:5 or 1:10 concentration, meaning that one part of the herbal material is prepared with five to ten parts (by weight) of the liquid. Liquid extracts are more concentrated than tinctures and are typically a 1:1 concentration. A dry extract form is the most concentrated form of an herbal product (typically 2:1 to 8:1) and is sold as a tablet, capsule, or lozenge.

Currently, no organization or government body regulates the manufacture or certifies the labeling of herbal preparations. This means you can't be sure that the amount of the herb contained in the bottle, or even from dose to dose, is the same as what is stated on the label. Some herbal preparations are standardized, meaning that the preparation is guaranteed to contain a specific amount of the active ingredients of the herb. However, it is still important to ask companies that are making standardized herbal products the basis for their product's guarantee. If consumers insist on an answer to this question, manufacturers of these herbal products may begin to implement more quality control processes, like microscopic, chemical, and biological analyses. Again, it is important to consult your doctor or an expert in herbal medicine for the recommended doses of any herbal products you are considering.